1. Field of the Invention
The present invention relates to thermoplastic polymer compositions, and more particularly relates to stabilized thermoplastic polymer compositions.
2. Description of the Related Art
Thermoplastic polymers such as polyolefins, for example, polypropylene and polyethylene, are generally well known. Such polymers can undergo instability in melt flow and undesirable colour changes during processing. Various types of additives such as phosphites, hindered phenols, hindered amine light stabilizers and nitrones have been added to polyolefins such as polypropylene. For example, CHAKRABORTY et al., Journal of Applied Polymer Science, Vol. 30, 3267-3281 (1985) entitled Mechanisms of Antioxidant Action: The Antioxidant Activity of Nitrones in Polypropylene, discloses the utilization of aldonitrones as melt stabilizers for polypropylene; and see CHAKRABORTY et al. Journal of Polymer Science: Polymer. Letters Edition, Vol. 22, 553-558 (1984) entitled Mechanisms of Antioxidant Action: Stabilization of Polymers by Spin Traps which discloses c-nitrose compounds as additives for polyolefins.
Consequently, there is a general need to improve the processing stability and colour of addition polymers such as polyolefins.